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Teen (Age 12-17) Marijuana Use and State Medical Marijuana Laws

  1. Comparison of Teen Marijuana Use in States Where Medical Marijuana Is Legal vs. States Where It Is Illegal, 1999-2005 Graph

  2. State by State Comparison of Teen Marijuana Use in 10 States with Legal Medical Marijuana, 1999-2005 Graph (A); Table (B)

  3. Statistically Significant Changes in Teen Past Month Marijuana Use, 1999-2005 Table

  4. States Ranked by Percentage of Teens Reporting Past Month Marijuana Use, 1999 and 2005 Table (A); Changes in Rank and Teen Use in States with Legal Medical Marijuana Table (B)

  5. Related Links and Sources

I. Comparison of Teen Marijuana Use in States Where Medical Marijuana Is Legal vs. States Where It Is Illegal, 1999-2005

From 1999 to 2005, states with legal medical marijuana had a higher average percentage of teen marijuana use than states where medical marijuana was illegal. Teen marijuana use decreased .69% in states where medical marijuana was illegal, and it decreased .01% in states where medical marijuana was legal.

Notes:
  1. ProCon.org created the graph using data for past month teen marijuana use from the Substance Abuse and Mental Health Services Administration (SAMHSA) National Household Survey on Drug Abuse (NHSDA), 1999-2005.
  2. This graph shows the average percentage of past month teen marijuana use from 1999 to 2005 for states where medical marijuana is legal, and the average for states where medical marijuana is illegal. Since medical marijuana became legal in different years in certain states, the percentage for each year on the line showing "legal" states includes only those states that had legalized medical marijuana on or before that year. The percentage for 1999 is therefore the average of Alaska, California, Maine, Oregon, and Washington; 2000-03 includes Alaska, California, Colorado, Hawaii, Maine, Nevada, Oregon, and Washington; 2004-05 includes Alaska, California, Colorado, Hawaii, Maine, Montana, Nevada, Oregon, Vermont, and Washington.
  3. Please note that data for all 50 states are only available for 1999 through 2005. In 1999, there were 5 states with legal medical marijuana; by 2005, 10 states had legalized it. As of Oct. 2007, there were 12 states with laws legalizing medical marijuana. Since Rhode Island and New Mexico passed medical marijuana in 2006 and 2007, in this graph they are included in the average of states where medical marijuana is illegal.
  4. State by state data on teen marijuana use prior to 1999 were not available.
 
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II. State by State Comparison of Teen Marijuana Use in 10 States with Legal Medical Marijuana, 1999-2005

Ten states had legalized medical marijuana by 2005; seven of those ten passed the laws between 1999 and 2005, the years for which the teen use data are available for all states.

Four of the seven states that passed medical marijuana laws between 1999 and 2005 had a decrease in average teen marijuana use the year after the law was passed. The other three states showed an increase the year after the law was passed. Six of the seven states had a lower percentage of teen use in 2005 than the year in which they legalized medical marijuana.

Eight of the ten states that had legalized medical marijuana as of 2005 had a lower percentage of teen use in 2005 than in 1999, while the other two ended with higher average teen use percentages in 2005 than in 1999.

A. Average Past Month Teen Marijuana Use Graph:

B. Average Past Month Teen Marijuana Use Table:

 
Average Past Month Teen Marijuana Use (%) in States with Legal Medical Marijuana 1999-2005
State
(year legalized)		 1999 2000 2001 2002 2003 2004 2005 ↓↑
(overall)
Alaska (1999) 10.40 8.65 9.88 9.44 11.08 12.02 9.71 ↓
California (1996) 7.70 7.50 8.16 7.60 7.66 8.52 7.50 ↓
Colorado (2000) 10.30 10.80 10.96 9.87 9.82 9.83 9.24 ↓
Hawaii (2000) 8.30 8.72 9.32 9.30 10.23 9.71 7.61 ↓
Maine (1999) 7.20 9.25 11.12 9.60 10.56 11.69 12.27 ↑
Montana (2004) 11.40 9.26 9.32 11.64 12.07 10.00 9.50 ↓
Nevada (2000) 11.60 9.54 9.32 11.24 9.58 7.82 6.98 ↓
Oregon (1998) 9.60 9.39 9.07 8.72 9.31 9.74 9.30 ↓
Vermont (2004) 8.40 10.62 13.20 13.31 13.32 11.11 10.54 ↑
Washington (1996) 9.90 8.70 9.56 8.93 9.11 7.98 6.83 ↓

Notes:
  1. ProCon.org created the graphs and tables using data for past month teen marijuana use from the Substance Abuse and Mental Health Services Administration (SAMHSA) National Household Survey on Drug Abuse (NHSDA), 1999-2005.
  2. The year in which each state passed its law is shown in parentheses in the graph legend. The seven states that adopted legalized medical marijuana between 1999 and 2005 have a diamond-shape marker showing the year in which the law was passed.

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III. Statistically Significant Changes in Teen Past Month Marijuana Use, 1999-2005

"Measuring the likelihood that an event occurs by chance is the idea behind 'statistical significance.' If there is, at most, a five percent chance of two events would happen together by coincidence, we may legitimately infer that there is a reason that the events occurred together. Such results are called statistically significant, and the events are considered correlated. If there is more than a five percent chance of occurring randomly, the possibility that the events occurred together just by luck is too high to dismiss, and we conclude nothing. The five percent line is arbitrary, but has become standard in the field of biomedical research; statistical significance is the golden measuring stick for evaluating data… For the sake of having a standard of some kind, scientists have agreed on p=.05. A result that is statistically significant has more weight in the scientific community than one that is not." Oct. 16, 2007 Statistical Assessment Service (STATS)

The table below shows changes in teen marijuana use that were statistically significant at the .05 level in states with legal medical marijuana, meaning there is a 95% certainty that the increase or decrease of teen marijuana use in a given state is not due to chance. By contrast, all changes that are not statistically significant might be due to chance in the survey population instead of representing an actual correlation. The data for statistical significance were taken from the Substance Abuse and Mental Health Services Administration (SAMHSA) National Household Survey on Drug Abuse (NHSDA), 1999-2005, which reported the p-values (observed significance levels) for the survey results.

None of the ten states with legal medical marijuana had a statistically significant increase in past month teen marijuana use between 1999 and 2005, but four states with legal medical marijuana did have statistically significant decreases.

 
Statistically Significant Changes (%)
State
(year legalized)		 1999-2000 2000-2001 2001-2002 2002-2003 2003-2004 2004-2005
Alaska (1999) - - - - - - 2.31
California (1996) - - - - - - 1.02
Colorado (2000) - - - - - -
Hawaii (2000) - - - - - - 2.10
Maine (1999) - - - - - -
Montana (2004) - - - - - 2.07 -
Nevada (2000) - - - - - -
Oregon (1998) - - - - - -
Vermont (2004) - - - - - -
Washington (1996) - - - - - -
National Average - +.40 - - - - .53

Notes:
  1. The lack of an increase in teen marijuana use in states that legalized medical marijuana appears to disprove the argument that legalizing medical marijuana would lead to increased teen use of marijuana for recreational purposes. The cause of the decrease in teen use, however, cannot be determined without additional information and statistical analysis.
 
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IV. States Ranked by Percentage of Teens Reporting Past Month Marijuana Use, 1999 and 2005

A. Rank and Percent Use by State:
The tables below show the rank of each state, including the District of Columbia and the national average, from highest percentage of past month teen marijuana use to lowest. The ten states that had legalized medical marijuana as of 2005 are shown in colors that correspond to the graphs in section II. The year in which each state legalized medical marijuana is noted in parentheses in the state rank table for 2005.

1999
Rank State % Teen Use
1 Delaware 13.9%
2 Massachussetts 11.9%
3 Nevada 11.6%
4 Montana 11.4%
5 Rhode Island 10.8%
6 New Hampshire 10.7%
7 Alaska 10.4%
8 Colorado 10.3%
9 Minnesota 9.9%
9 Washington 9.9%
11 Oregon 9.6%
District of Columbia 9.6%
12 Illinois 9.2%
12 New Mexico 9.2%
14 Maryland 8.8%
15 Indiana 8.7%
16 Connecticut 8.6%
17 Vermont 8.4%
18 Hawaii 8.3%
18 Wisconsin 8.3%
20 Michigan 7.8%
20 Wyoming 7.8%
22 California 7.7%
23 North Dakota 7.6%
National 7.4%
24 South Carolina 7.4%
27 Arizona 7.3%
27 Arkansas 7.3%
27 New Jersey 7.3%
28 Maine 7.2%
29 West Virginia 7.1%
31 Ohio 6.9%
31 South Dakota 6.9%
33 New York 6.8%
33 North Carolina 6.8%
34 Mississippi 6.7%
37 Kansas 6.6%
37 Louisiana 6.6%
37 Missouri 6.6%
38 Georgia 6.4%
40 Oklahoma 6.3%
40 Pennsylvania 6.3%
41 Florida 6.2%
43 Nebraska 6.1%
43 Utah 6.1%
45 Idaho 5.9%
45 Virginia 5.9%
46 Texas 5.7%
47 Alabama 5.6%
48 Kentucky 5.3%
50 Iowa 5.2%
50 Tennessee 5.2%

2005
Rank State % Teen Use
1 Maine (1999) 12.27%
2 Rhode Island 10.82%
3 Vermont (2004) 10.54%
4 Alaska (1999) 9.71%
5 Montana (2004) 9.5%
6 Massachusetts 9.49%
7 Oregon (1998) 9.3%
8 Colorado (2000) 9.24%
9 New Mexico 9.11%
10 Connecticut 8.88%
11 New Hampshire 8.59%
12 New York 8.4%
13 Arizona 8.2%
14 Wisconsin 8.13%
15 Arkansas 7.83%
16 Minnesota 7.82%
16 North Carolina 7.82%
18 Kentucky 7.73%
19 Hawaii (2000) 7.61%
20 Missouri 7.53%
21 California (1996) 7.5%
22 Michigan 7.49%
23 Ohio 7.43%
24 Florida 7.29%
25 Delaware 7.24%
National 7.2%
26 Oklahoma 7.1%
27 West Virginia 7%
28 Nevada (2000) 6.98%
29 Maryland 6.88%
29 Pennsylvania 6.88%
29 Wyoming 6.88%
District of Columbia 6.87%
32 Washington (1996) 6.83%
33 Kansas 6.79%
33 South Dakota 6.79%
35 Alabama 6.72%
36 Indiana 6.54%
37 New Jersey 6.47%
38 South Carolina 6.43%
39 Illinois 6.35%
40 Idaho 6.24%
41 Georgia 6.07%
42 Iowa 5.98%
42 Tennessee 5.98%
44 Nebraska 5.88%
45 North Dakota 5.82%
46 Mississippi 5.79%
47 Texas 5.76%
48 Louisana 5.75%
49 Utah 5.69%
50 Virginia 5.31%

B. Change in Rank and Percent Use in States with Legal Medical Marijuana:
Five states with legal medical marijuana ranked higher in 2005 than in 1999, meaning the teen marijuana use in those states went up relative to other states; four states ranked lower; one state remained the same. Eight states with legal medical marijuana had a lower percentage of teen marijuana use in 2005 than in 1999, while two states had a higher percentage. Please note on the table below that a "+" indicates the state moved closer to rank #1 (highest teen marijuana use), while a "-" indicates that the state moved closer to rank #50 (lowest teen marijuana use).

Changes in Rank and Teen Use in States with Legal Medical Marijuana
State Change in rank from 1999 to 2005 Change in teen use from 1999 to 2005
Alaska +3 -.69%
California +1 -.20%
Colorado -- -1.06%
Hawaii -1 -.69%
Maine +27 +5.07%
Montana -1 -1.90%
Nevada -25 -4.62%
Oregon +4 -.30%
Vermont +14 +2.14%
Washington -23 -3.07%
Net -1 -5.32%

Notes:
  1. The data on past month teen marijuana use provided by Substance Abuse and Mental Health Services Administration (SAMHSA) were presented to one decimal place for 1999 (0.0) and switched to hundreths (0.00) from 2000-2005.
  2. Mark Eddy, Specialist in Illicit Drug Control Policy at the Congressional Research Service (CRS), in his July 27, 2007 report Medical Marijuana: Review and Analysis of Federal and State Policies, noted a common argument of critics of medical marijuana:

    "They point to the 1999 National Household Survey on Drug Abuse (NHSDA), which 'reveals that those states which have passed medical marijuana laws have among the highest levels of past-month marijuana use, of past-month other drug use, of drug addiction, and of drug and alcohol addiction.' [...] It is at least possible, however, that this analysis confuses cause with effect...It is logical to assume that the states with the highest prevalence of marijuana usage would be more likely to approve medical marijuana programs, because the populations of those states would be more knowledgeable of marijuana’s effects and more tolerant of its use." CRS Report for Congress: “Medical Marijuana: Review and Analysis of Federal and State Policies” (PDF) 11.2MB
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V. Related Links and Sources:

  1. CRS report: “Medical Marijuana: Review and Analysis of Federal and State Policies” (PDF) 11.2MB
  2. Summary of State Medical Marijuana Laws
  3. Has legalizing medical marijuana led to increased drug abuse among children and adolescents?
  4. 1999 SAMHSA Report: “1999 State Data from National Survey on Drug Abuse” (PDF) 852 KB
  5. 2000 SAMHSA Report: “2000 State Data from National Survey on Drug Abuse” (PDF) 1.07 MB
  6. 2001 SAMHSA Report: “2001 State Data from National Survey on Drug Abuse” (PDF) 1 MB
  7. 2002 SAMHSA Report: “2002 State Data from National Survey on Drug Abuse” (PDF) 497 KB
  8. 2003 SAMHSA Report: “2003 State Data from National Survey on Drug Abuse” (PDF) 537 KB
  9. 2004 SAMHSA Report: “2004 State Data from National Survey on Drug Abuse” (PDF) 531 KB
  10. 2005 SAMHSA Report: “2005 State Data from National Survey on Drug Abuse” (PDF) 437 KB

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